The invention is directed to apparatus designed to provide safe and efficient filtration of smoke plume generated by laser-surgical, electrosurgical, radiosurgical, cautery, hyfrecators and electrocautery devices.
Surgical smoke evacuation systems are designed to capture the smoke and plume generated during surgical procedures in which there is thermal destruction of tissue or bone. The plume from vaporized tissue contains small particles and gases that could be potentially hazardous. If not evacuated the materials can become airborne and deposit in the respiratory tracts of the surgical team. The type of surgical instruments, the characteristics of tissue, and the surgeon=s technique affect the quantity and characteristics of the smoke plume. A surgical smoke evacuator is in essence a vacuum pump, usually footswitch operated, that incorporates one or more filters to remove particles from the suctioned air-stream at the surgical site. A hose, typically of plastic, disposable or reusable, connects the pump to a disposable or autoclavable wand serving as a nozzle that is usually held about 5 cm. from the tissue to remove smoke generated by the surgical procedure. Because the constraints of some surgical procedures can prevent placement of the nozzle close to the tissue, smoke evacuators should capture smoke effectively at up to 15 cm. Adequate protection from potentially dangerous smoke plume can only be achieved when the plume is successfully captured before it comes into contact with the patient and surgical staff. This smoke entrainment requires that the evacuator airflow change the smoke direction and draw it into the hose via the wand. The ability of a smoke evacuator to collect the surgical plume is highly dependent on three factors; the distance of the wand from the source, the volumetric airflow entering the wand and hose, and the local velocities of the room air.
Successful smoke plume filtration is heavily dependent on several factors. They include:
1. The air flow rate which affects the speed and effectiveness to capture the smoke plume.
2. The extended wand needs to be clog-free to prevent suctioning in any-large objects.
3. The location of the safety wand should allow it to be brought to the close vicinity of the smoke source.
3. An effective micro-pre-filter is needed to have enough area to allow the air flow through and capture the micro particles at the same time.
4. The diameter of the hose affects the speed of the air flow.
5. The air must stay in active charcoal of a main filter long enough to allow the charcoal to act to remove any odors.
6. The motor system must not create or add any particles to the exhausting air.
A principal object of the invention is a filtration system that provides a strong air suction flow rate to be able to capture the smoke plumes before they escape.
A further object of the invention is a low cost filtration system that is efficient and reliable.
These objects are achieved in accordance with one aspect of the invention by a filtration system that captures and removes the smoke plume using several stages of filtration processes, including a first micro-pre-filter to filter out the most particles and harmful elements at this stage followed by passage of the smoke plume through a main vacuum suction unit and filter to filter out the remaining particles and any odors. Preferably, the main filter comprises fine charcoal which helps remove the odors.
In a preferred embodiment, means are provided to monitor the degree of pollution of the main filter to warn users when it is desirable or necessary to replace the main filter.
In accordance with another feature of the invention, means are provided to ensure reasonably constant air mass flow to protect against significant clogging of the system which could result in undesirable passage of harmful particles into the environment.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention, like reference numerals or letters signifying the same or similar components.